The present invention relates to perfect layer coil winding apparatuses for making perfect layer coils in which a wire is wound round a bobbin so as to form a large number of parallel turns.
The term "perfect layer coil" used here and hereinafter is defined to mean a coil that is formed in such a manner that, placing in close contact with the turn already wound on a coil bobbin, the next turn is wound one after another successively along the axial direction of the bobbin.
As a winding apparatus for forming the perfect layer coils there has been hitherto proposed a winding machine in which a pair of rollers for holding a wire therebetween and for defining a supply position of the wire are forced to move in such a manner that the supply position of the wire follows a wire winding position on a bobbin with the delay of a predetermined amount to supply the wire to the bobbin with a predetermined angle of lag and to wind the wire along a coil formed by this time on the bobbin so that a desired coil is continuously formed.
In such a winding machine, a pair of rollers for defining the supply position of wire are moved usually by feed means (formed by a combination of screw and nut) in synchronism with the rotation of the bobbin, and are instantaneously displaced by a desired amount and reversed in their moving direction with a solenoid or the like at the end of each layer of the coil to conduct the winding operation for the next layer. The proposed winding machine has a drawback that, when the number of turns per layer is varied due to the non-uniformity in the width of bobbin or the diameter of wire, the position of wire which is wound round the bobbin falls into disorder. Further, since the wire has to be wound closely along a flange of the bobbin at the initial stage of the winding operation in order to form a perfect layer coil, it is required to manually form first one or two turns prior to an automatic winding operation, and thus the winding machine is very low in operation efficiency.